The study included 74 children in Montreal, aged 7 to 11, who were enrolled in a six-week school program to improve their sleep habits.

An average increase of about 18 minutes of sleep each night led to significant improvements in report card grades, especially in English and math, according to the study published recently in the journal Sleep Medicine.

The findings show that small, cumulative increases in children's sleep may lead to better marks at school, lead researcher Reut Gruber, a professor at McGill University in Montreal, said in a university news release.

The researchers said parents should ensure children get enough sleep every night and that schools need to find ways to include sleep education programs in their health curriculum.